1. Field of the Invention
The present invention relates to a caliper brake, and more particularly, a caliper brake in which a return spring that allows a piston performing brake within a brake cylinder to be returned to its original position when a brake pressure is released, is modularized with a pressurization rod part that pressurizes the piston so that a spring cage that fixes the return spring to the pressurization rod part can be conveniently and stably assembled.
2. Description of the Related Art
In general, caliper-type brakes are brakes that perform a brake operation by pressurizing and stopping a brake disc interposed between a piston and a frictional pad of a fork with a brake force applied to the piston, wherein a rotatative force of a brake lever that rotates by a parking cable during the brake operation is switched to a straight motion, thus generating the brake force of the piston.
In this case, caliper brakes can be classified in various manners according to a method of switching a rotatative motion of the brake lever to the straight motion. Thus, representative examples thereof may be ball in ramp (BIR) type caliper brakes. Caliper parking brakes, in particular, among them, as indicated by reference numeral 101 of FIG. 1, when a parking cable is pulled during parking brake, if a brake lever 100 connected to the parking cable is rotated, an input ramp 103 that is mounted in a cylinder 105 so as to rotate in synchronization with a rotation axis of the brake lever 100, is rotated.
As a result, when an uneven surface processed at a front side of the input ramp 103 and an uneven surface of an output ramp 107 that is matched to the uneven surface of the input ramp 103 in a state in which a ramp roller is interposed between the input ramp 103 and the output ramp 107, shake in a straight line direction due to rotation of the input ramp 103, the output ramp 107 makes a straight motion in an axial direction. Thus, a rotatative force that is introduced into the caliper parking brake 101 via the brake lever 100 is switched to the straight motion of the output ramp 107 and is used to pressurize a piston 109 mounted on a front end of the cylinder 105 forward. A brake disc 110 is pressurized between the piston 109 pressurized in this manner and a fork 111 via frictional pads 113, thus performing brake.
As described above, in the caliper parking brake 101 according to the related art, a recoil spring 115 is interposed between the output ramp 107 and the piston 109, as illustrated in FIG. 1. The recoil spring 115 inserted into a circumference of the output ramp 107 allows the output ramp 107 that pressurizes the piston 109 during brake to be returned to its original position when brake is released.
In this case, the recoil spring 115 is confined by a spring cage 121 having a tripod shape. To this end, the spring cage 121 includes a plurality of footpad parts 123 that constitute sidewalls of a body and are spaced apart from each other by a predetermined distance. Thus, hanging holes 125 are open to rear ends of the plurality of footpad parts 123 and thus are coupled to a plurality of hanging protrusions 117 that protrude from an outer circumferential surface of the output ramp 107 in a radial direction. Thus, the recoil spring 115 is fixed between the output ramp 107 and the piston 109.
Meanwhile, in the caliper parking brake 101 according to the related art, the hanging holes 125 should be hung in the hanging protrusions 117 so as to fix the recoil spring 115 inserted into the output ramp 107 using the tripod-shaped spring cage 121. To this end, the spring cage 121 has elasticity so that rear ends of the footpad parts 123, diameters of which are enlarged to the outside, can be further widened in the radial direction. Thus, the entire thickness of the footpad parts 123 cannot increase. As a result, the strength of the footpad parts 123 is deteriorated and thus the footpad parts 123 are easily deformed, which results in lowered durability and coupling force of the spring cage 121 and reduction in an usable life-span of the spring cage 121.
In contrast, when the entire thickness of the footpad parts 123 increases, elasticity of the footpad parts 123 is lost, and the spring cage 121 cannot be coupled to the output ramp 107 in a snap manner. Thus, assembling and manufacturing efficiency may be lowered like when assembling becomes difficult.
Also, since a direction in which force is applied to the spring cage 121 by the recoil spring 115 and a direction in which the spring cage 121 is prevented from escaping from the output ramp 107 via the hanging holes 125 and the hanging protrusions 117 coincide with each other in an axial line direction, even when coupling of the hanging holes 125 and the hanging protrusions 117 is not slightly complete, the spring cage 121 escapes from the output ramp 107 easily. Thus, reliability of assembling is lowered, and an assembling defect occurs comparatively easily.